JP7460677B2 - Method and apparatus for projecting color images - Google Patents

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit under 35 U.S.C. § 119 of U.S. Application No. 62/237,989, entitled PROJECTION SYSTEM AND METHOD, filed October 6, 2015, which is hereby incorporated by reference for all purposes.

One aspect of the invention relates to the generation of a desired pattern of light in a field sequential projection system. Another aspect of the invention relates to the generation of a desired pattern of light in a projection system having multiple stages of imaging elements. These aspects may be applied individually or in combination. Embodiments of the invention provide projectors, components for projectors, and related methods.

The present invention has multiple aspects, which may be implemented individually or in various combinations. These aspects include, but are not limited to, an image projection apparatus, an image projection method, and an apparatus and method for mixing light steered by a phase modulator onto an imager with additional light.

One aspect of the invention provides a method for projecting a color image. The method includes configuring an imaging element to spatially modulate light according to a pattern corresponding to each of a series of fields associated with a corresponding color, and illuminating the imaging element with light of the corresponding color. Illuminating the imaging element with light of the corresponding color includes directing the light of the corresponding color onto a phase modulator that is controlled to provide a phase pattern that serves to steer the light of the corresponding color to a desired location on the imaging element. The phase modulator is refreshed at a frequency less than the frequency at which the fields are presented. In some embodiments, the phase modulator is refreshed once per frame (where a frame includes one complete cycle of fields of different colors).

In some embodiments, a separate phase modulator is provided for each of the plurality of colors, and the method includes selecting one of the plurality of phase modulators corresponding to one of the plurality of colors. one into a field corresponding to a different one of the plurality of colors.

In some embodiments, a separate region of the phase modulator is associated with each of the plurality of colors, and illuminating the imager with light of the corresponding color is associated with the corresponding color. associated with said corresponding color while said region of said phase modulator is controlled to provide said phase pattern that serves to steer light of said corresponding color to a desired location on said image sensor. directing the light of the corresponding color so as to illuminate the area of the phase modulator that has been irradiated. In some embodiments, the method comprises determining one of the regions of the phase modulator corresponding to one of the plurality of colors to correspond to a different one of the plurality of colors. A refresh step is provided during the field.

The regions may have different sizes. For example, the plurality of colors may include blue, and one of the regions associated with the color blue may be larger than at least one other of the regions; The color may include green, and one of the regions associated with the color green may be larger than at least one other of the regions or in the image being displayed. Based on the relative output levels for the plurality of colors, the relative size of the regions can be controlled. In some embodiments, the method comprises periodically reassigning some or all of the plurality of colors to different ones of the plurality of regions of the phase modulator. For example, the series of fields may be repeated once in each of the series of frames, and the method may repeat some or all of the plurality of colors of the plurality of colors of the phase modulator in each of the frames. The method may include reassigning to different ones of the regions.

In some embodiments, the same phase pattern is used for each of the multiple colors.

In some embodiments, the plurality of colors includes red, green, and blue.

In some embodiments, the image sensor includes a DMD.

In some embodiments, the phase modulator comprises an LCOS.

In some embodiments, illuminating the imaging element with the light of the corresponding color further comprises combining additional light of the corresponding color with the light steered by the phase modulator or replacing the light steered by the phase modulator with light that bypasses the phase modulator. Combining the additional light with the light steered by the phase modulator can generate a light beam that illuminates the imaging element from a common direction. In some embodiments, the additional light includes light collected from a DC spot generated by the phase modulator. In some embodiments, the additional light includes light from an additional light source. In some embodiments, the light steered by the phase modulator has a first polarization, the additional light has a second polarization different from the first polarization, and the light steered by the phase modulator is combined with the additional light at a polarizing beam splitter. In some embodiments, the light steered by the phase modulator has a first wavelength, the additional light has a second wavelength different from the first wavelength, and the light steered by the phase modulator is combined with the additional light at a dichroic element. In some embodiments, the light source emits light having components in two polarization states, and the method comprises separating the components of the emitted light, where the additional light comprises one of the components of the emitted light and the light steered by the phase modulator comprises the other of the components of the emitted light. In some such embodiments, the method comprises altering the relative intensities of the components of the two polarization states by passing the emitted light through a polarization shifting element, and controlling the polarization shifting element to vary the proportion of the light in each of the separated components based on the brightness of the image being projected.

Another exemplary aspect provides a method for projecting a color image that includes illuminating an imaging device with a color of light. said step operating in a first mode based on the brightness or power level of said image, said step providing a phase pattern that serves to steer said colored light to a desired location on said image sensor. directing said light of said color onto a phase modulator controlled to operate in a second mode, said light of said color not interacting with said phase modulator; phase modulation in which light of said color is directed from a light source onto an imager or is controlled to provide a phase pattern that serves to steer said light of said color to a desired location on said imager; either directed onto the device, combined with additional light of the color, and the combined light is directed onto the imaging device.

Another example aspect provides an apparatus for projecting an image. The apparatus is configured to implement any of the methods described herein.

Additional aspects of the invention and example embodiments of the invention are illustrated in the drawings and/or described in the description below.

The accompanying drawings illustrate non-limiting examples of embodiments of the present invention. These drawings show an exemplary projector and also illustrate an exemplary method.

1 to 9 relate to a method and apparatus for displaying images in a field sequential manner. Also, field sequential projectors that use secondary colors or white as the field can produce these images by turning on more than one light source at once and adjusting the amplitude image on a digital micromirror device (“DMD”). can be represented using the diagram.

1 is a schematic diagram showing a red light path through a projector operating according to a first approach, in which only the red channel phase liquid crystal on silicon ("LCOS") is illuminated and the DMD directs only red pixels to the screen.

1 is a schematic diagram showing the green light path through a projector operating according to the first approach, in which only the LCOS of the green channel phase is illuminated and the DMD directs only green pixels to the screen.

1 is a schematic diagram showing a blue light path through a projector operating according to a first approach; FIG. In the blue light path, only the blue channel phase LCOS is illuminated and the DMD directs only the blue pixels to the screen.

4 is a schematic diagram showing a red light path through a projector operating according to the second approach. In the red light path, only the red spatial portion of the phase LCOS is illuminated, and the DMD directs only red pixels to the screen. A single LCOS also displays green and blue phase patterns at different positions, but these are not illuminated in FIG.

FIG. 3 is a schematic diagram showing a green light path through a projector operating according to a second approach; In the green optical path, only the green spatial portion of the phase LCOS is illuminated and the DMD directs only the green pixels to the screen. A single LCOS also displays a red phase pattern and a blue phase pattern at different locations, but these are not illuminated in FIG. 5.

FIG. 4 is a schematic diagram showing a blue light path through a projector operating according to a second approach; In the blue light path, only the blue spatial portion of the phase LCOS is illuminated, and the DMD directs only the blue pixels to the screen. A single LCOS also displays red phase patterns and green phase patterns at different locations, but they are not illuminated in FIG. 6.

1 is a schematic diagram showing a red light path through a projector operating according to a third approach. In the red light path, a luminance phase pattern on the LCOS is illuminated, and the DMD attempts to direct only red pixels to the screen and block unwanted red light elsewhere. The luminance phase pattern is generated from a weighted sum (or other method) of the red, green and blue phase patterns.

1 is a schematic diagram showing a green light path through a projector operating according to a third method. In the green light path, a luminance phase pattern on the LCOS is illuminated, and the DMD attempts to direct only green pixels to the screen and block unwanted green light elsewhere. The luminance phase pattern is generated from a weighted sum (or other method) of the red, green and blue phase patterns.

1 is a schematic diagram showing a blue light path through a projector operating according to a third method. In the blue light path, a luminance phase pattern on the LCOS is illuminated, and the DMD attempts to direct only blue pixels to the screen and block unwanted blue light elsewhere. The luminance phase pattern is generated from a weighted sum (or other method) of the red, green and blue phase patterns.

10-13 relate to a method and apparatus for displaying images using multiple optical paths.

We show how to implement "fixed polarization" with two separate laser sources.

FIG. 1 is a schematic diagram showing how to implement “random polarization” as would be ideal in a fiber-coupled laser source.

FIG. 2 is a schematic diagram showing how to perform "variable polarization". This is the most complex and expensive, but allows the most efficient use of the laser.

Figure 3 shows how to perform "fixed wavelength" with two separate laser sources.

Throughout the following description, specific details are set forth in order to provide a more complete understanding of the invention. However, the invention may be practiced without these details. In other instances, well-known elements have not been shown or described in detail to avoid unnecessarily obscuring the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

This disclosure describes both techniques for performing field sequential color projection and also techniques for illuminating a DMD or other imaging device. These aspects of the present technology may be applied individually or in any combination. Field sequential display

Images can be formed in a projection system by using separate imaging elements for each of the red, green, and blue lights, and then combining these images on a screen. However, projector manufacturers typically want to make projectors as cheaply as possible. High quality, high resolution imaging elements such as DMDs can be expensive.

A high dynamic range projection system may have multiple stages of imaging elements. These elements may work together to increase the contrast of the system and/or reduce the black level.

In some high dynamic range (“HDR”) projection systems, a phase modulator (eg, an LCOS phase modulator) may be combined with a DMD amplitude modulator. An example of a projection system of this type is e.g. described in WO 2015/054797. That specification is hereby incorporated by reference for all purposes. Embodiments described herein may implement any of the features described in WO 2015/054797.

To reduce component costs, HDR projectors may use field sequential technology so that only one DMD is required. As described herein, in some embodiments, one phase modulator may be used instead of three.

DMDs typically have a fast response time. Specifically, they can change the patterns they display much faster than humans can perceive. Rather than having a separate DMD for each color (and thereby using three DMDs), one can have a single DMD and rapidly time-division multiplex the fields through the single DMD. Although the colors are displayed one at a time, all of the colors in the image are integrated by the human eye because the time-division multiplexing occurs faster than humans can perceive the individual fields. This is known in the industry as "field sequential projection."

Many phase modulators have relatively slow response times. For example, the phase modulator may be LCOS based. A human observer can easily recognize individual color fields in field sequential applications where a single LCOS is reconfigured for the next color between fields.

Individual LCOS panels typically cannot handle as much light as a single DMD without damage or degradation. In systems with very high light output, two or more LCOS panels may be required to illuminate a single DMD. Blue light can cause more LCOS panel degradation than light with longer wavelengths (eg, red light). Exemplary field sequential embodiment

Three exemplary methods for performing field sequential projection in a projector using LCOS phase modulators and DMD amplitude modulators are described below. Each of these methods can be implemented using a single DMD. The following description assumes a field sequential projector that uses red, green, and blue as three sequential fields. Variations of the method described below may use different colors as fields, more or fewer primary colors, one or more secondary colors (eg, combinations of primary colors), and/or the white color. First approach - 3 phase modulators and 1 imager

The "first approach" uses three LCOS phase modulators: one for redirecting red light, one for redirecting green light, and one for redirecting blue light. The first approach can provide high light throughput and can provide high contrast and a wide color gamut.

A device 10 that can operate according to the first approach is shown schematically in FIGS. 1 to 3. Device 10 includes a plurality of light sources 11 (shown as 11R, 11G and 11B). Light source 11 may include, for example, a laser. In the illustrated embodiment, light source 11R emits red light, light source 11G emits green light, and light source 11B emits blue light.

Each of the light sources 11 is associated with a corresponding phase modulator 12 (12R, 12G, and 12B are shown), which may each comprise, for example, an LCOS. Light modulated by any of the phase modulators 12 illuminates an imager 14, which may comprise, for example, a DMD. The imager 14 modulates the light, which is then projected onto a screen 15.

A controller 16 adjusts the operations of the light source 11, phase modulator 12, and image sensor 14 to display an image according to the image data. In each of a plurality of sequential fields, each field being a period of time, one light source is active. In an exemplary embodiment, the frame rate is in the range of 20 to 100 frames per second, and each frame is divided into three fields.

As shown in FIG. 1, in the first field, the red light source 11R may be active. Red light from red light source 11R is steered to a desired location (e.g., a location corresponding to an area where the image data specifies a higher red intensity) by a phase pattern applied to phase modulator 12R, and/or or steered away from undesirable locations (eg, locations corresponding to areas where the image data specifies low red intensity). The red light modulated by phase modulator 12R is then directed onto an imager 14 which is controlled by the image data to modulate the incident light in a pattern specified for red light.

In the second and third fields, the above process is repeated for green and blue light, respectively, as shown in FIGS. 2 and 3.

In this exemplary embodiment, phase modulator 12 does not need to be refreshed any faster than the frame rate of interest (1/3 of the rate at which the fields are shown in this example). The image sensor 14 is refreshed for all fields.

For each field, the controller 16 may perform several steps, including setting the imager to a pattern corresponding to the corresponding color, refreshing the phase modulator corresponding to a different color (the phase modulator corresponding to the current color may have been refreshed in a previous field), and turning on the light source of the current color, so that light from that light source is steered by the phase modulator, modulated by the imager, and projected onto the screen 15.

The duration of each field is short enough that the different colors displayed in each field are integrated by the observer's eye and perceived as a color image.

In an exemplary embodiment, three phase modulators (one per color) are sequentially illuminated by a modulated light source (usually a laser light source). Each phase modulator is controlled to provide a customized phase pattern for the wavelength and profile of the incident beam, which generates a steered image at a steered image plane located a known distance away from the phase modulator. The steered image may deliver a higher intensity if the image data specifies a higher brightness for that color, and a lower intensity if the image data specifies a lower brightness for that color. Optics are provided to relay the steered images of all three color channels along a common path to an imaging device (e.g., to a head with a DMD). Each steered image provides the desired steered illumination of the DMD or other imaging device. The optics relaying the steered images to the imaging device may optionally provide one or more of magnification, improved telecentricity, and increased etendue, which may lead to improved image quality and compatibility with DMD heads.

The optics that guide each of the steered images to the imager can be located in the optical path either after the three separate steered image beams are made telecentric, or before the steering image plane. This is easily done because the steered images are monochromatic (the primary colors of the laser) and have a high F-number (low divergence).

The phase modulators can be configured to display customized patterns for each color channel, such that each steered image features a desired brightness profile for that color channel as well as consistent framing (image size and shape) with the steered images of the other color channels. To achieve consistent framing, the distance between each phase modulator and its corresponding steered image plane can be selected based on criteria such as wavelength, beam divergence, and beam profile.

In embodiments operating according to the first approach, the period during which each light source is activated (the on-time of the R, G, and B light sources) may be varied based on the desired steering brightness level and color. For example, the R, G, and B light sources may be activated during a period to produce a steered full screen white at the D65 white point. If the intensity of the light output by each light source can be modulated, the desired brightness and color of the displayed image will depend on one or more of the on-time of each light source in the corresponding field, the output of each light source, and the duty cycle of each light source. can be set by controlling. Some advantages of modulated light sources include the ability to use lower power lasers, and to use them with shorter duty cycles and higher required power (e.g. 30% red at twice the normal maximum power). This includes being able to drive. Second approach - one space-splitting phase modulator and one imager

The "second approach" uses a single phase modulator that is spatially divided into multiple regions. The phase modulator is controlled such that each region provides one phase pattern per color (ie, a phase pattern that properly steers the light for the corresponding color). A projector 40 according to an exemplary embodiment is shown in FIGS. 4, 5, and 6.

In an exemplary embodiment, the light sources 11 (again provided, for example, 11R, 11G and 11B) emit red, green and blue light, respectively. The red, green and blue lights are each directed to illuminate a corresponding region 43R, 43G and 43B of phase modulator 42 (which may be, for example, LCOS). Regions 43R, 43G, and 43B are controlled to provide phase patterns for red, green, and blue light, respectively. These phase patterns direct the light onto the imager 14. The image sensor 14 is set to modulate the current color of light in each field. The light modulated by the image sensor 14 is projected onto the screen 15.

The second approach may offer cost savings compared to the first approach because only a single phase modulator is required. The second approach may compromise contrast because light of an individual color may not be steered as precisely as possible if only a portion of the phase modulator is used to steer the light as would be possible if the entire phase modulator were used to steer the light. The second approach also allows for the use of the full color gamut made possible by the primary colors, which may be the primary colors of a laser.

In some embodiments, the physical locations on the LCOS of regions 43 corresponding to different colors may be changed from time to time for wear leveling. The blue region 43B may deteriorate over time faster than the red region 43R.

The division of phase modulator 42 into regions 43 need not be equal. The size of some or all of the regions 43 may be different. For example, the size of region 43 may be proportional to output requirements for different colors. Optionally, region 43 may be resized in real time as output requirements for different colors of light change. Region 43G may be made larger than the other regions 43 due to the increased sensitivity of the human visual system to the precision of green light, or region 43B for blue may be made larger due to the increased sensitivity of the human visual system to the precision of green light, or the region 43B for blue may suffer from reduced power density and degradation. may be increased to result in a reduction in

In the second approach, each region 43 of the phase modulator 42 needs to be refreshed at most once per frame. All regions 43 of the phase modulator 42 can be refreshed in one operation. If different regions 43 of the phase modulator 42 can be refreshed individually, one region 43 can be refreshed while the light is being steered by another region 43.

If a single phase modulator is spatially divided, a geographic portion of the LCOS is used for each individual color. Each part is driven with a corresponding phase image. All three phase images are computed, scaled, and combined into a single phase image that is applied to the LCOS phase modulator.

Each light source 11 (eg, each laser) is directed to illuminate only a corresponding color region on the LCOS modulator 42. No part of the LCOS should be illuminated by more than one laser color.

For wear leveling, the laser can sometimes be redirected to different areas of the LCOS to change the location of the blue light. Blue light degrades LCOS devices faster than red or green light.

In an exemplary embodiment implementing the second approach, a single phase modulator is sequentially illuminated by each of a plurality of modulated light sources, each light source having a corresponding portion of the single phase modulator. irradiate only. The size of the portion of the phase modulator assigned to each color may be determined by the desired quality of the steered image (generally, all else being equal, the more pixels assigned to one color, the more pixels are assigned to one color. (The more the number, the better the quality of the steered image will be for that color). Each color-specific portion of the phase device can be controlled to provide a customized phase pattern for that color's wavelength of light, incident beam profile/nature, etc. This causes the steered image formed by the portion to overlap with the steered images of other channels (ie, the framing should be consistent).

In some embodiments for forming RGB steered images at a steering image plane at a common distance from the phase modulator, the phase pattern for each color portion may be calculated using target images with different geometries (i.e., the target images for different colors may be scaled differently to compensate for the effect of wavelength on steering). As in some embodiments applying the first approach, the optics relaying the steered image to the imager may optionally provide one or more of magnification, improved telecentricity and increased etendue, which may lead to improved image quality and compatibility with DMD heads.

Color combining optics are optionally present, but are typically not required after the phase modulator. This is because the steered images for each color can be provided to a common steering image plane in a field sequential manner. Color combining optics may be provided to aggregate the incident light from the three parts of the phase modulator. As a result, the paths taken by the R beam, G beam, and B beam when they enter the image sensor are spaced close to each other and become parallel or nearly parallel. If the incident beams are not perfectly parallel, the corresponding color-specific phase patterns may provide tilt correction. Third approach - one common phase modulator and one imager

The "third approach" uses a single LCOS phase modulator that displays a single phase pattern for each frame. This approach is the most cost effective method. The reason is that this approach uses a single phase modulator and only one phase pattern (instead of three) needs to be calculated so that cheaper computational hardware can be used. It is. The third approach may compromise color gamut. This approach may allow more unwanted colors to leak through the system (due to not steering unwanted color components). The third approach may provide approximately the same contrast as the first approach.

7, 8 and 9 schematically illustrate a device 70 configured for operation according to the third approach. The device 70 includes a light source 11 (again provided, for example, 11R, 11G and 11B) that emits red, green and blue light, respectively. The red, green, and blue light are each directed to illuminate a phase modulator 72 (which may include, for example, an LCOS). Phase modulator 72 is configured with a phase pattern selected to steer light from any one of light sources 11 onto imager 14 . The same phase pattern can be used for two or more different colors of light.

The image sensor 14 is set to modulate the current color of light in each field. The light modulated by the image sensor 14 is projected onto the screen 15.

If the intensity distributions of consecutive frames are the same or similar, phase modulator 72 may be updated with a new pattern once per frame, or less. Luminance phase modulation image

When a single phase image is used to direct light for all colors (e.g., when applying the third approach described above), that single phase image should direct enough light onto the DMD in every area where every color is present to illuminate all image features.

The DMD is controlled to block any unwanted colors from the screen for each image feature. The DMD's ability to block light determines the size of the final color gamut (because on a pure red object, small amounts of green and blue light will leak through).

One technique for generating a luminance image from an RGB image (i.e., image data that specifies R, G, and B values for each pixel) is to convert the RGB image to the XYZ color space and use the Y channel as the luminance image.

In a specific embodiment implementing the third approach, a single phase modulator is sequentially illuminated by modulated light sources of different colors. Each light source may illuminate substantially all of the active area of the phase modulator. A common phase pattern is used to steer the light for all three color channels. This ensures that the steered images have the desired brightness profile and that the combination of the steered images results in the same color point.

Because the phase pattern is common for all colors, beams can be directed from different color light sources to be incident on the phase modulator at different angles. This produces three steered images at different distances and along different orientations relative to the phase modulator. Separate color combining and relay optics can then be used to recombine, shape, and relay the separate steered images onto the imager. This configuration can be used to match the framing of the different colors.

Another technique for matching the framing of different color channels is to make light beams of different colors incident parallel to the phase modulator, but with some or all of the beams slightly diverging or converging. to modify the collimation of some or all of the beams. The amount of divergence or convergence of each beam may be selected to compensate for the different distances that the steered images would otherwise form for different colors. The steered image may then be relayed onto an imaging device. As with other approaches, projectors applying the third approach may optionally include optical elements that have magnifying power, improve telecentricity, and/or increase etendue. Approach to illuminating the image sensor

Another aspect of the invention provides methods and apparatus for more directly illuminating the DMD and/or selectively illuminating the DMD or other amplitude modulator with light that has been pre-modulated in some way and/or delivered more directly from the light source to the amplitude modulator. Such methods and apparatus may direct a portion of the light from the light source to the DMD, bypassing the phase modulator or other upstream light attenuating components, and/or may add one or more secondary light sources directed to illuminate only the DMD. Directly illuminating the DMD may help increase efficiency when displaying bright scenes.

The method and apparatus of this aspect may be applied individually or in combination with the methods and apparatus of any of the first to third approaches described above. Such methods and apparatus may also be applied in color projection systems that include three complete sets of LCOS and DMDs.

In high dynamic range projection systems, the LCOS phase modulator may be combined with an amplitude modulator (eg, a DMD) such that the LCOS phase modulator is steered into position over the amplitude modulator when necessary.

For all-white or very bright images, it is more efficient to illuminate the DMD directly, as opposed to using a phase modulator to steer the light onto the DMD. LCOS panels typically cannot handle as much light energy as DMDs. As a result, the total light throughput capacity of the system may be increased by allowing at least some light to bypass the LCOS modulator, at least when bright images are being projected.

Some embodiments combine light that is being steered by the phase modulator with light that is bypassing the phase modulator such that the combined light reaches the DMD at a uniform angle of incidence. This addresses the problem that DMDs are often very sensitive to the angle at which the light approaches. The light bypassing the LCOS and the light steered by the LCOS may be combined such that they all enter the DMD at the same angle (ie, within a narrow range of incident angles that the DMD can accommodate). In some embodiments, this is accomplished by using a combiner that combines light entering the combiner from two different directions into a combined light beam that leaves the combiner in a common direction. The combiner may comprise, for example, a polarizing beam splitter or a dichroic element.

Figures 10 through 13 show an exemplary apparatus that can be operated to illuminate an imager, such as a DMD, with light steered by a phase modulator (and/or processed by some other upstream light-attenuating optical element), with light directed to illuminate the imager without being steered by a phase modulator, or with a mixture of the two. The light steered by the phase modulator and the light not steered by the phase modulator can come from the same light source or different light sources.

Light can be selectively propagated along different paths using polarization. For example, the light may be P-polarized, S-polarized, or both (randomly polarized). S-polarized light and P-polarized light are polarized at right angles to each other. S-polarized light and P-polarized light may be separated from each other with a polarizing beam splitter. P-polarized light and S-polarized light can be combined into random polarized light, and random polarized light can be split into P-polarized light and S-polarized light using a polarizing beam splitter.

Laser sources with random polarization have large components of both S and P polarization. Free-space lasers tend to only produce S-polarized or P-polarized light, depending on the physical orientation of the laser. Physically rotating the laser can change whether the emitted light is S or P polarized.

LCOS phase modulators tend to work well with only a single type of polarization (depending on orientation). For example, if an LCOS panel is oriented toward P-polarized light, the LCOS panel will tend to reflect S-polarized light directly back toward the light source, rather than allowing S-polarized light to pass through. right.

Using an LCOS modulator to steer light from a P-polarized source allows the steered P-polarized light to be combined with unsteered S-polarized light before directing the resulting composite random polarization into a DMD amplitude modulator. Fixed Polarization Approach

In some embodiments, two separate light sources, eg, a family of lasers, one for producing S-polarized light and one for producing P-polarized light, may be used (a "fixed polarization" approach). Light from one of the sources (eg, P-polarized) is directed by a steering element (eg, LCOS) to illuminate the imaging device (eg, DMD). Light from the other light source (eg, an S-polarized light source) is directed to illuminate the imaging element without interacting with (ie, bypassing) the steering element. If the detour light (e.g., S-polarized light) is not desired at the imager because the scene being displayed is very dark, the source of the detour light (e.g., the S-polarized light source) may be reduced in power or turned off. and/or the detour light may be directed away from the imager and/or be prevented from reaching the imager.

Figure 10 shows a projector 100 that implements the "fixed polarization" approach with two separate laser light sources 11S and 11P. Light source 11P illuminates phase modulator 12 with P polarization. Phase modulator 12 is set with a phase pattern that steers the P polarization onto imager 14, such as a DMD, by combiner 108, which in this embodiment comprises a polarizing beam splitter.

The light source 11S emits S-polarized light. The S-polarized light is homogenized by passing through optical system 109 and directed onto combiner 108 . Optical system 109 uniformly disperses the light passing through it (or at the imager in another desired manner). Optical system 109 may include, for example, a fly's eye array and/or other homogenizer.

Any light from the light source 11S is combined with the light from the light source 11P in the combiner 108 and directed to illuminate the image sensor 14.

A despeckle element 107 is optionally provided in the optical path upstream from the image sensor 14. The despeckle element despeckles the combined beam. An optional despeckle element may be provided, for example, just before the DMD amplitude modulator.

Since DMDs and other amplitude modulators do not completely block light, in scenes with many dark spots it is desirable to prevent light that does not originate from the phase modulator from hitting the DMD.

A control system 101 may be connected to control the light sources 11P and 11S. In some embodiments, the light sources 11P and 11S have individually controllable outputs. In some embodiments, the control system 101 may control the output of light from the light source 11S. In some embodiments, the control system 101 may switch the light source 11S on or off depending on whether additional light is required. The control system 101 may also control the application of data to the phase modulator 12 and the imager 14, and the overall timing of the operation of the device 100. Random Polarization (or Non-Polarized Approach)

A single light source (perhaps a fiber-coupled LED) may be used that emits both S and P polarizations (a "random polarization" approach). In this case, a polarizing beam splitter may be used to separate the S and P components of the incident light into two separate paths. Attenuators such as apertures and/or shutters, and/or controllable redirecting elements such as movable mirrors or lenses may be provided in the S (bypass) light path to attenuate light that bypasses the phase modulator when a dark black is required. The P component may be modulated (e.g. steered by a phase modulator) before entering the amplitude modulator.

FIG. 11 is a schematic diagram of an example apparatus 110 configured to operate according to a random polarization approach. The device 110 includes a light source 11SP that emits light that includes multiple separable polarization components (eg, an S-polarization component and a P-polarization component). Light source 11SP advantageously, but optionally, may include a fiber-coupled laser source.

Preferably, the light emitted by the light source 11SP has good quality as a beam (ie, low etendue), allowing it to be collimated with low divergence. This in turn allows for better separation of the S and P polarization components into paths 111A and 111B at beam splitter 112 (e.g., with better uniformity and higher throughput). It becomes possible.

Homogenizer 115 is preferably selected such that the etendue of the light does not increase significantly along path 111B. This facilitates combining the light beams in the combiner 114. One suitable choice for homogenizer 115 is a combination of lenses, including a fly's eye lens array. This is the case if such a combination can result in homogenization with minimal increase in etendue.

The embodiments shown in any of Figures 10-13 may benefit from using light with a small etendue. A small etendue promotes efficiency, uniformity, etc. when different light beams are combined.

The light emitted by light source 11SP is split based on polarization into two paths 111A and 111B by beam splitter 112. The path 111A transmits light so that the phase modulator 12 illuminates the image sensor 14. Path 111B bypasses phase modulator 12. Paths 111A and 111B join upstream from image sensor 14 at synthesizer 114.

Path 111B includes homogenizer 115 and aperture 116. Aperture 116 can be controlled to adjust the amount of light delivered by bypass path 111B and incident on image sensor 14.

Control system 115 may control aperture 116 to selectively adjust the amount of light from path 111B that is allowed to reach imager 14. Control system 115 may also control the application of data to phase modulator 12 and imager 14 and the overall timing of operation of apparatus 110. Variable polarization approach

The "variable polarization" approach is similar to the random polarization approach, but provides a technique for varying the relative intensities of separable polarization components of the light emitted by the light source. For example, a device implementing a variable polarization approach may include a half-wave plate that can be rapidly rotated within 90 degrees. By setting the rotation of the half-wave plate on a frame-by-frame basis, the mixture of S-polarized and P-polarized light sent to the polarizing beam splitter can be adjusted. The resulting beam can be used as input to the random polarizer described above, allowing more light (e.g. more S polarization) to be sent directly to the DMD for bright scenes, and more Allows light (eg, more P polarization) to be sent directly to the LCOS for dark scenes.

Figure 12 is a schematic diagram showing an apparatus 120 that implements the "variable polarization" approach. The embodiment of Figure 12 is typically more complex and expensive to implement than the embodiments of Figures 10 and 11, but allows for the most efficient use of the laser.

The portion of device 120 shown inside box 121 is common to device 110 described above. The device 120 comprises a light source 11 that emits polarized light. The polarization of the light can be changed by polarization shifting element 122. The polarization shifting element can be controlled to change the relative amounts of the two polarization states in the light that can be separated by the beam splitter 112. For example, the polarization shifting element 122 may include a half-wave plate and a motor or other actuator connected to set the rotation angle of the half-wave plate.

A control system 125 may control polarization shifting element 122 to selectively adjust the amount of light incident on path 111B. Control system 125 may also control the application of data to phase modulator 12 and imager 14 and the overall timing of operation of apparatus 120. Wavelength-based separation approach

Another approach to controlling the path light takes is to separate the light based on wavelength. Light of different wavelengths can be separated by, for example, dichroic elements or multilayer thin films. Thus, a system can be formed with two sets of red, green and blue colors. Red, green and blue can be chosen such that a large color gamut can be produced with either set and the absence of one is not noticeable.

In a similar fashion to that described above, two light sources with similar wavelengths, e.g., two lasers, can be used. In this case, a color beam splitter is used to send one wavelength to an LCOS or other phase modulator, and the other wavelength is provided directly (e.g., without significant attenuation) to a DMD or other amplitude modulator (a "fixed wavelength" approach). The two wavelengths can correspond to the same primary color (e.g., the two wavelengths can be different red, green, or blue).

Figure 13 shows a schematic of an apparatus 130 that implements the "fixed wavelength" approach with two separate laser sources 11R1 and 11R2 emitting light of different wavelengths. The wavelengths can be closely spaced, for example, separated by a difference of 5 nm or 10 nm. In other embodiments, the two wavelengths can be more widely spaced. The wavelengths can be two shades of the same color, for example, two shades/tones of red, green or blue.

The light source 11R1 illuminates the image sensor 14 using the phase modulator 12. The light source 11R2 illuminates the image sensor 14 through an optical path that bypasses the phase modulator 12. Light from light sources 11R1 and 11R2 is combined in combiner 132. Optical element 139 homogenizes the light in optical path 11R2.

A control system 135 may be connected to control the light sources 11R1 and 11R2. In some embodiments, the light sources 11R1 and 11R2 have individually controllable outputs. In some embodiments, the control system 135 may control the output of light from the light source 11R2. In some embodiments, the control system 135 may switch the light source 11R2 on or off depending on whether additional light is required. The control system 135 may also control the application of data to the phase modulator 12 and the imager 14, and the overall timing of the operation of the apparatus 130. DC Spot Reuse

A phase modulator may generate a DC spot that does not correspond to image features. It is usually desirable to steer the DC spot to the outside of the image. Light from this spot can be recovered and sent to a DMD or other imaging device, eg, as diffused light. Whether light from the DC spot is directed to the imaging device and/or the amount of light directed from the DC spot to the imaging device is controlled on a frame-by-frame or field-by-field basis in some embodiments. The control may be based on the power level calculated for the field or frame. At higher power levels (brighter images), light may be directed from the DC spot to the imaging device, while at lower power levels, less light may be directed from the DC spot to the imaging device, or less light may be directed from the DC spot to the imaging device. may not be directed toward the imaging device. A wide range of optical systems can be used to transmit light from the DC spot to the imaging device. In some embodiments, an arrangement similar to that shown in FIG. 10 is used to collect light from the DC spot and combine it with light modulated by a phase modulator upstream from the imaging device. obtain. The optical path for the light from the DC spot may include optical elements such as one or more homogenizers or light diffusers to diffuse the additional illumination provided by the light from the DC spot at the imaging device. If necessary, a polarization shifting element may be provided to change the polarization of the light from the DC spot to facilitate combining the light from the DC spot and the light steered by the phase modulator. This technique can be combined with any of the above techniques or used alone.

The various approaches described herein may be embodied in a projector configured to implement these approaches. Additionally, any of the described methods for field sequential imaging may optionally be combined with any of the described methods for providing direct illumination of the light modulator. LCOS is an example of a phase modulator. Other embodiments may use other types of phase modulators. A DMD is an example of an amplitude modulator. Other embodiments may use other types of amplitude modulators instead of a DMD.

In an exemplary embodiment, video data is processed to identify brightness of frames. If the frame is dark, the phase modulator is configured for the frame by steering the light from the light source onto the amplitude modulator and controlling the amplitude modulator to modulate the steered light. can be controlled to display a captured image. In frame sequential images, this can be done separately for each color subframe. If the frame is bright, the amplitude modulator can be illuminated by light that is not initially steered by the phase modulator, either in addition to, or instead of, light steered by the phase modulator. The amplitude modulator can be controlled to display a (bright) image.

In some exemplary embodiments, the apparatus shown in any one of FIGS. can be used to provide one of the following: In some embodiments, two or more or all of the color channels modulate their respective colors of light in parallel (ie, simultaneously). In other embodiments, some or all of the color channels may operate in a field sequential or time interleaved manner. In some cases, field sequential operation is implemented using one of approaches 1, 2, or 3 described above for some or all of the color channels.

In some embodiments, multiple colors from separate color channels having the overall architecture shown by FIGS. 11, 12 or 13 are emitted simultaneously and combined to provide white light.

The displays described herein include a controller configured to control one or more phase modulators and one or more amplitude modulators to display an image or other light pattern, whereby image data is a supplied input or data store, a light source (which may entirely comprise a laser, other solid-state light source, or other light source), a projection lens, a display screen (front or rear projection), other optical elements in the optical path (e.g. , lenses, mirrors, collimators, diffusers, etc.), power supplies, focusing systems, thermal management systems, etc., which are not shown for clarity. Interpretation of terms

Unless the context clearly requires otherwise, throughout this specification and claims, "comprises," "comprises," and the like are to be construed in an inclusive sense, i.e., "including but not limited to," as opposed to an exclusive or exhaustive sense. "Connected," "coupled," or any variation thereof, means any connection or coupling between two or more elements, whether direct or indirect, and the coupling or coupling between the elements may be physical, logical, or a combination thereof. The words "herein," "above," "below," and words of similar import, when used to describe this specification, shall refer to this specification as a whole, and not to any particular portion of this specification. When referring to a list of two or more items, "or" includes all of the following interpretations of this word, namely, any of the items in that list, all of the items in that list, and any combination of the items in that list. The singular forms "a," "an," and "the" also include any appropriate plural meaning.

Directional terms such as "vertical," "lateral," "horizontal," "upper," "lower," "forward," "rearward," "inward," "outward," "vertical," "lateral," "left," "right," "front," "rear," "upper," "lower," "lower," "above," "below," and the like, when used in this specification and any appended claims, are dependent upon the specific orientation of the device being described and shown. The subject matter described herein may assume various alternative orientations. Thus, these directional terms are not precisely defined and should not be interpreted narrowly.

Embodiments of the present invention may be implemented using specifically designed hardware, configurable hardware, programmable data processors configured by providing software (which may optionally comprise "firmware") executable on a data processor, special purpose computers or data processors specifically programmed, configured or constructed to perform one or more steps in the methods detailed herein, and/or control systems including combinations of two or more of these. Examples of specifically designed hardware are logic circuits, application specific integrated circuits ("ASICs"), large scale integrated circuits ("LSIs"), very large scale integrated circuits ("VLSIs"), and the like. Examples of configurable hardware are one or more programmable logic devices, such as programmable array logic ("PALs"), programmable logic arrays ("PLAs"), and field programmable gate arrays ("FPGAs"). Examples of programmable data processors are microprocessors, digital signal processors ("DSPs"), embedded processors, graphics processors, mathematical coprocessors, general purpose computers, server computers, cloud computers, mainframe computers, computer workstations, and the like. For example, one or more data processors in control circuitry for a device may implement the methods described herein by executing software instructions in program memory accessible to those processors.

Processing may be centralized or distributed. When processing is distributed, information, including software and/or data, may remain centralized or distributed. Such information may be exchanged between different functional units by means of a communications network, such as a local area network (LAN), a wide area network (WAN) or the Internet, wired or wireless data links, electromagnetic signals or other data communications channels.

For example, although processes or blocks are shown in a given order, alternative examples may perform routines with the steps or use systems with the blocks in a different order. Also, some processes or blocks may be deleted, moved, added, subdivided, combined, and/or modified to provide alternatives or subcombinations. Each of these processes or blocks may be implemented in a variety of different ways. Also, although processes or blocks are sometimes depicted as being performed sequentially, the processes or blocks may instead be performed in parallel or at different times.

Additionally, although the elements are sometimes depicted as being executed sequentially, they may instead be executed concurrently or in a different order. It is therefore intended that the following claims be interpreted as including all such modifications within their intended scope.

The software and other modules may reside on servers, workstations, personal computers, tablet computers, image data encoders, image data decoders, PDAs, video projectors, AV receivers, displays (such as televisions), digital cinema projectors, media players, and other devices suitable for the purposes described herein. Those skilled in the art will appreciate that aspects of the system may be implemented in other communications, data processing, or computer system configurations, including consumer electronics (e.g., video projectors, AV receivers, displays such as televisions, and the like), set-top boxes, network PCs, minicomputers, mainframe computers, and the like.

The invention may also be provided in the form of a program product. The program product may comprise any non-transitory medium carrying a set of computer readable instructions that, when executed by a data processor, cause the data processor to perform the methods of the invention. A program product according to the invention may be in any of a wide variety of forms. The program product may be, for example, a magnetic data storage medium including floppy disks, a hard disk drive, an optical data storage medium including CD-ROM, a DVD, an electronic data storage medium including ROM, flash RAM, EPROM, hardware. It may include non-transitory media such as embedded or pre-programmed chips (e.g. EEPROM semiconductor chips), nanotechnology memory or the like. Computer readable signals on the program product may optionally be compressed or encrypted.

In some embodiments, the present invention may be implemented in software. For clarity, "software" includes any instructions executed on a processor, and may include (but is not limited to) firmware, resident software, microcode, and the like. As known to those skilled in the art, both the processing hardware and the processing software may be centralized or distributed, in whole or in part (or a combination thereof). For example, the software and other modules may be accessible via local memory, via a network, via a browser or other application in a distributed computing environment, or via other means suitable for the above purposes. In some embodiments, image data is processed by a processor executing software instructions to generate control signals for a phase modulator. The software may operate in real time in some (but not all) embodiments.

When a component (e.g., a software module, processor, assembly, device, circuit, etc.) is referred to above, unless otherwise indicated, references to that component (including references to "means") should be construed to include any components that perform the function of the described component (i.e., are functionally equivalent) as equivalents of that component, including components that are not structurally equivalent to the disclosed structures that perform the functions shown in the exemplary embodiments of the present invention.

Specific examples of systems, methods, and apparatus have been described herein for illustrative purposes. These are examples only. The techniques provided herein may be applied to systems other than the exemplary systems described above. Many changes, modifications, additions, omissions, and substitutions are possible within the scope of the invention. The invention includes variations of the described embodiments that will be apparent to those skilled in the art. Such variations include variations obtained by omitting features, elements, and/or operations by replacing features, elements, and/or operations with equivalent features, elements, and/or operations, mixing and matching features, elements, and/or operations from different embodiments, combining features, elements, and/or operations from the embodiments described herein with features, elements, and/or operations of other technologies, and/or combining features, elements, and/or operations from the described embodiments.

Accordingly, it is intended that the following appended claims and any claims hereafter introduced be interpreted as including all such modifications, permutations, additions, omissions, and subcombinations that may reasonably be construed. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be accorded the broadest interpretation consistent with the description as a whole.
[Other possible items]
[Item 1]
for each of a series of fields associated with a corresponding color, configuring an imager to spatially modulate light according to a pattern corresponding to the corresponding color; and illuminating the imager with light of the corresponding color;
illuminating the imaging element with light of the corresponding color comprises directing the light of the corresponding color onto a phase modulator that is controlled to provide a phase pattern that serves to steer the light of the corresponding color to a desired location on the imaging element;
the phase modulator is refreshed at a frequency less than the frequency at which the series of fields is presented;
A method for projecting a color image.
[Item 2]
a separate phase modulator is provided for each of the plurality of corresponding colors;
The method includes refreshing one of a plurality of the phase modulators corresponding to one of the plurality of corresponding colors during a field corresponding to a different one of the plurality of corresponding colors.
The method according to item 1.
[Item 3]
a separate region of the phase modulator associated with each of the plurality of corresponding colors;
illuminating the imaging element with light of the corresponding color comprises directing the light of the corresponding color to illuminate the separate areas of the phase modulator associated with the corresponding color while the separate areas of the phase modulator associated with the corresponding color are controlled to provide the phase pattern that serves to steer the light of the corresponding color to a desired location on the imaging element.
The method according to item 1.
[Item 4]
refreshing one of the plurality of distinct regions of the phase modulator corresponding to one of the plurality of corresponding colors during a field corresponding to a different one of the plurality of corresponding colors.
The method according to item 3.
[Item 5]
a plurality of said distinct regions having different sizes;
The method according to item 3.
[Item 6]
the plurality of corresponding colors includes a blue color, and one of the plurality of distinct regions associated with the blue color is larger than at least one other of the plurality of distinct regions;
The method according to item 5.
[Item 7]
the plurality of corresponding colors includes green, and one of the plurality of distinct regions associated with the color green is larger than at least one other of the plurality of distinct regions;
The method according to item 5.
[Item 8]
controlling relative sizes of the plurality of distinct regions based on relative output levels for the plurality of corresponding colors in a displayed image.
The method according to item 5.
[Item 9]
periodically reassigning some or all of the plurality of corresponding colors to different ones of the plurality of distinct regions of the phase modulator.
The method according to item 3.
[Item 10]
said sequence of fields repeating once in each of a sequence of frames;
the method comprising the step of reallocating some or all of the corresponding colors to different ones of the distinct regions of the phase modulator in each of the series of frames.
The method according to item 9.
[Item 11]
the same phase pattern is used for each of the plurality of corresponding colors;
The method according to item 1.
[Item 12]
the plurality of corresponding colors includes red, green and blue;
12. The method according to any one of items 1 to 11.
[Item 13]
illuminating the imaging element with the corresponding color light further comprises combining additional light of the corresponding color with the light steered by the phase modulator.
13. The method according to any one of items 1 to 12.
[Item 14]
combining the additional light with the light steered by the phase modulator to generate a light beam that illuminates the imaging element from a common direction.
Item 14. The method according to item 13.
[Item 15]
the additional light includes light collected from a DC spot generated by the phase modulator.
15. The method according to item 13 or 14.
[Item 16]
The additional light includes light from an additional light source.
16. The method according to any one of items 13 to 15.
[Item 17]
the light steered by the phase modulator has a first polarization and the additional light has a second polarization different from the first polarization, and the light steered by the phase modulator is combined with the additional light at a polarizing beam splitter.
17. The method according to item 15 or 16.
[Item 18]
the light steered by the phase modulator has a first wavelength and the additional light has a second wavelength different from the first wavelength, and the light steered by the phase modulator is combined with the additional light at a dichroic element.
17. The method according to item 15 or 16.
[Item 19]
the first wavelength and the second wavelength differ by 20 nm or less;
19. The method according to item 18.
[Item 20]
The light source emits light having components of two polarization states;
The method comprises separating the components of the emitted light;
the additional light comprises one of the components of the emitted light;
the light steered by the phase modulator is composed of the other of the components of the emitted light;
18. The method according to any one of items 13 to 17.
[Item 21]
altering the relative intensities of the components of the two polarization states by passing the emitted light through a polarization shifting element;
and controlling the polarization shifting element to vary the proportion of light in each of the separated components based on a brightness of an image being projected.
21. The method according to item 20.
[Item 22]
the polarization shifting element comprises a half-wave plate;
controlling the polarization shifting element comprises rotating the half-wave plate.
22. The method according to item 21.
[Item 23]
1. A method for projecting a color image, comprising:
illuminating an imaging device with incident light of a color;
and operating the imaging device to spatially modulate the incident light,
The step of illuminating the imaging device includes:
I) operating in a first mode, the light of the colors being directed onto a phase modulator that is controlled to provide a phase pattern that serves to steer the light of the colors to a desired location on the imaging element;
II) operating in a second mode,
a. light of said color is directed from a light source onto said imaging element without interacting with said phase modulator, or b. light of said color is directed onto said phase modulator, which is controlled to provide a phase pattern that serves to steer said light of said color to a desired location on said imaging element, and combined with additional light of said color, and the combined light is directed onto said imaging element.
Method.
[Item 24]
directing light of a certain color onto a phase modulator that is controlled to provide a phase pattern that serves to steer the light of that color to a desired location on the imaging device;
combining additional light of said color with said steered light;
directing the combined light, including the steered light and the additional light, onto the imager, thereby illuminating the imager with the light of the color.
A method for projecting an image.
[Item 25]
The additional light is diffuse.
25. The method according to item 24.
[Item 26]
combining the additional light with the steered light steered by the phase modulator to generate a light beam that illuminates the imaging element from a common direction.
26. The method according to item 24 or 25.
[Item 27]
the additional light includes light collected from a DC spot generated by the phase modulator.
27. The method according to any one of items 24 to 26.
[Item 28]
The additional light includes light from an additional light source.
28. The method according to any one of items 24 to 27.
[Item 29]
the light steered by the phase modulator has a first polarization and the additional light has a second polarization different from the first polarization, and the light steered by the phase modulator is combined with the additional light at a polarizing beam splitter.
29. The method according to item 27 or 28.
[Item 30]
the light steered by the phase modulator has a first wavelength and the additional light has a second wavelength different from the first wavelength, and the light steered by the phase modulator is combined with the additional light at a dichroic element.
30. The method according to item 28 or 29.
[Item 31]
the first wavelength and the second wavelength differ by 20 nm or less;
31. The method according to item 30.
[Item 32]
the light of said color is emitted by a light source emitting light having components of two polarization states;
The method comprises separating the components of the emitted light;
the additional light comprises one of the components of the emitted light;
the light steered by the phase modulator is composed of the other of the components of the emitted light;
32. The method according to any one of items 24 to 31.
[Item 33]
varying the relative intensities of the two polarization state components by passing the emitted light through a polarization shift element and controlling the polarization shift element to vary the proportion of the light in each of the separated components based on the brightness of the image being projected.
33. The method according to item 32.
[Item 34]
illuminating a spatial amplitude modulator with a plurality of combined light beams, the first beam including steered light and the second beam including uniformly distributed light;
A method for displaying an image.
[Item 35]
homogenizing the light in the second beam prior to combining the first and second beams.
35. The method according to item 34.
[Item 36]
spatially modulating the light in the first beam;
36. The method according to item 34 or 35.
[Item 37]
spatially modulating the light in the first beam comprises phase modulating the first beam.
37. The method according to item 36.
[Item 38]
the first beam is uniform before being spatially modulated;
38. The method according to item 37.
[Item 39]
the light in the first beam and the light in the second beam are in corresponding separable first and second polarization states.
39. The method according to any one of items 34 to 38.
[Item 40]
the first beam and the second beam originate from a light source that produces light having the first polarization state and the second polarization state.
40. The method according to item 39.
[Item 41]
the first and second polarization states being P and S polarization states, or S and P polarization states, respectively;
41. The method according to item 39 or 40.
[Item 42]
the light source includes a first light emitting element and a second light emitting element that emit light in the first polarization state and light in the second polarization state, respectively;
41. The method according to item 40.
[Item 43]
The light source includes a single light emitting element.
41. The method according to item 40.
[Item 44]
splitting light from the light source into the first beam and the second beam using a polarizing beam splitter.
Item 44. The method according to item 43.
[Item 45]
The light source includes a polarized light source and a rotatable half-wave plate.
41. The method according to item 40.
[Item 46]
varying the relative intensities of the first beam and the second beam by rotating the rotatable half-wave plate.
Item 46. The method according to item 45.
[Item 47]
splitting light from the light source into the first beam and the second beam using a polarizing beam splitter.
47. The method according to item 45 or 46.
[Item 48]
the first beam originates from a first light source and the second beam originates from a second light source;
40. The method according to item 39.
[Item 49]
The wavelength of the first light source is within a range of about 5 nm to about 20 nm from the wavelength of the second light source.
49. The method according to item 48.
[Item 50]
the wavelengths of the first and second light sources are two shades of the same color;
50. The method according to item 49.
[Item 51]
combining the first beam and the second beam using a combiner.
51. The method according to any one of items 48 to 50.
[Item 52]
the light in the first beam and the light in the second beam are within corresponding separable first and second wavelengths.
39. The method according to any one of items 34 to 38.
[Item 53]
narrowing the second beam by adjusting an aperture in the path of the second beam.
53. The method according to any one of items 34 to 52.
[Item 54]
performed for each of a plurality of color channels when displaying a color image;
54. The method according to any one of items 34 to 53.
[Item 55]
A full color system that combines three or more channels of separate primary colors, comprising:
Each of the separate primary colors is delivered according to the method of any one of items 34 to 54.
Full color system.
[Item 56]
the light in each of the first and second beams has a similar, small etendue or spread;
56. The full color system of item 55.
[Item 57]
1. An apparatus for projecting a color image, comprising:
a plurality of color channels, each associated with a corresponding color and having a light source of the corresponding color;
at least one phase modulator;
An imaging element;
an optical element arranged to direct light from the light source for each of the plurality of color channels to illuminate the imager along a path that includes phase modulation by the at least one phase modulator;
a control system connected to control the light source, the at least one phase modulator, and the imager to project images in a series of fields, each field associated with a corresponding color of one of the plurality of color channels, the control system being operative to configure the imager to spatially modulate light in the fields according to a pattern corresponding to the corresponding color, and to control the light source of the corresponding color to emit light that is phase modulated by the at least one phase modulator and directed onto the imager;
The control system further resets a phase pattern by which the at least one phase modulator modulates the light into each of the plurality of color channels at a frequency less than a frequency at which the series of fields are presented.
Device.

Claims (34)

A method for projecting a color image, the method comprising:
for each of a series of fields, each of said series of fields being associated with a corresponding color, configuring a light modulating element to spatially modulate light according to a pattern corresponding to said corresponding color; irradiating with light of the corresponding color;
Irradiating the light modulating element with the correspondingly colored light comprises controlled phase modulation to provide a phase pattern that serves to steer the correspondingly colored light to a desired location on the light modulating element. directing the light of the corresponding color onto a vessel;
the phase modulator is refreshed at a frequency less than the frequency at which the series of fields are shown;
the same phase pattern is used for each of the plurality of corresponding colors;
The method further comprises directing light of each of the plurality of corresponding colors to a different angle of incidence on the phase modulator.
Method. a separate phase modulator is provided for each of the plurality of corresponding colors;
The method includes transmitting one of the plurality of phase modulators corresponding to one of the plurality of corresponding colors into a field corresponding to a different one of the plurality of corresponding colors. Provides a refresh stage,
The method according to claim 1. a separate region of the phase modulator associated with each of the plurality of corresponding colors;
illuminating the light-modulating element with light of the corresponding color comprises directing the light of the corresponding color to illuminate the separate areas of the phase modulator associated with the corresponding color while the separate areas of the phase modulator associated with the corresponding color are controlled to provide the phase pattern that serves to steer the light of the corresponding color to a desired location on the light-modulating element.
The method of claim 1. refreshing one of the plurality of distinct regions of the phase modulator corresponding to one of the plurality of corresponding colors during a field corresponding to a different one of the plurality of corresponding colors.
The method according to claim 3. the plurality of corresponding colors includes a blue color, and one of the plurality of distinct regions associated with the blue color is larger than at least one other of the plurality of distinct regions;
The method according to claim 3. the plurality of corresponding colors includes green, and one of the plurality of distinct regions associated with the green color is larger than at least one other of the plurality of distinct regions;
The method according to claim 3. controlling the relative sizes of the plurality of distinct regions based on relative power levels for the plurality of corresponding colors in the displayed image;
The method according to claim 3. periodically reassigning some or all of the plurality of corresponding colors to different ones of the plurality of distinct regions of the phase modulator.
The method according to claim 3. said sequence of fields repeating once in each of a sequence of frames;
the method comprising the step of reallocating some or all of the corresponding colors to different ones of the distinct regions of the phase modulator in each of the series of frames.
The method according to claim 8. the phase modulator has an actuation region;
irradiating the light modulation element with the correspondingly colored light comprises directing the correspondingly colored light to substantially all of the active area of the phase modulator;
The method according to claim 1. the light of each of the plurality of corresponding colors forms an image at a different distance from or orientation relative to the phase modulator;
The method includes combining a plurality of the images formed by the light of each of the plurality of corresponding colors.
The method of claim 1. illuminating the light-modulating element with the corresponding color of light further comprises combining additional light of the corresponding color with the light steered by the phase modulator.
12. The method according to any one of claims 1 to 11. combining the additional light with the light steered by the phase modulator to generate a light beam illuminating the light modulation element from a common direction.
The method of claim 12. the light steered by the phase modulator has a first polarization and the additional light has a second polarization different from the first polarization, and the light steered by the phase modulator is combined with the additional light at a polarizing beam splitter.
14. The method according to claim 12 or 13. 1. An apparatus for projecting a color image, comprising:
a plurality of color channels, each associated with a corresponding color and having a light source of the corresponding color;
at least one phase modulator;
A light modulation element;
an optical element arranged to direct light from the light sources for each of the plurality of color channels to illuminate the light-modulating element along a path that includes phase modulation by the at least one phase modulator;
a control system connected to control the light source, the at least one phase modulator, and the light modulation elements to project an image in a series of fields, each associated with a corresponding color of one of the plurality of color channels, the control system being operative to configure the light modulation elements to spatially modulate light in the fields according to a pattern corresponding to the corresponding color, and to control the light sources of the corresponding colors to emit light that is phase modulated by the at least one phase modulator and directed onto the light modulation elements, the control system being configured to apply a same phase pattern for each of the plurality of corresponding colors, and light of each of the plurality of corresponding colors being directed at a different angle of incidence to the at least one phase modulator;
the control system is further configured to reset a phase pattern by which the at least one phase modulator modulates the light into each of the plurality of color channels at a frequency less than a frequency at which the series of fields is presented.
Device. 1. A method for projecting a color image, comprising:
for each of a series of fields associated with a corresponding color, configuring a light modulation element to spatially modulate light according to a pattern corresponding to the corresponding color; and illuminating the light modulation element with light of the corresponding color;
illuminating the light-modulating element with light of the corresponding color comprises directing the light of the corresponding color onto a phase modulator that is controlled to provide a phase pattern that serves to steer the light of the corresponding color to a desired location on the light-modulating element;
the phase modulator is refreshed at a frequency less than the frequency at which the series of fields is presented;
illuminating the light-modulating element with the corresponding color of light further comprises combining additional light of the corresponding color with the light steered by the phase modulator;
the light steered by the phase modulator has a first polarization and the additional light has a second polarization different from the first polarization, and the light steered by the phase modulator is combined with the additional light at a polarizing beam splitter.
Method. combining the additional light with the light steered by the phase modulator to generate a light beam illuminating the light modulation element from a common direction.
17. The method of claim 16. the additional light comprises light collected from a DC spot generated by the phase modulator;
17. The method according to claim 16. The additional light includes light from an additional light source.
17. The method of claim 16. the additional light has a second wavelength different from the wavelength of the light steered by the phase modulator;
17. The method according to claim 16. a separate phase modulator is provided for each of the plurality of corresponding colors;
The method includes refreshing one of a plurality of the phase modulators corresponding to one of the plurality of corresponding colors during a field corresponding to a different one of the plurality of corresponding colors.
17. The method of claim 16. a separate region of the phase modulator associated with each of the plurality of corresponding colors;
illuminating the light-modulating element with light of the corresponding color comprises directing the light of the corresponding color to illuminate the separate areas of the phase modulator associated with the corresponding color while the separate areas of the phase modulator associated with the corresponding color are controlled to provide the phase pattern that serves to steer the light of the corresponding color to a desired location on the light-modulating element.
17. The method of claim 16. refreshing one of the plurality of distinct regions of the phase modulator corresponding to one of the plurality of corresponding colors during a field corresponding to a different one of the plurality of corresponding colors.
23. The method of claim 22. the plurality of corresponding colors includes a blue color, and one of the plurality of distinct regions is associated with the blue color and is larger than at least one other of the plurality of distinct regions;
24. The method of claim 23. the plurality of corresponding colors includes a green color, and one of the plurality of distinct regions is associated with the green color and is larger than at least one other of the plurality of distinct regions;
24. The method of claim 23. controlling the relative sizes of the plurality of distinct regions based on relative power levels for the plurality of corresponding colors in the displayed image;
24. The method according to claim 23. periodically reassigning some or all of the plurality of corresponding colors to different ones of the plurality of distinct regions of the phase modulator;
23. The method according to claim 22. said sequence of fields repeating once in each frame of the sequence of frames;
The method includes reallocating some or all of the corresponding colors to different ones of the distinct regions of the phase modulator in each frame of the series of frames.
28. The method of claim 27. the same phase pattern is used for each of the plurality of corresponding colors;
17. The method according to claim 16. The phase modulator has an active area, and the step of irradiating the light modulating element with the corresponding colored light includes applying the corresponding colored light to substantially all of the active area of the phase modulator. having a step of directing;
30. The method of claim 29. The light of each of the plurality of corresponding colors forms an image at a different distance from the phase modulator or at a different orientation with respect to the phase modulator, and the method includes: composing the plurality of images formed by each of the lights;
30. The method of claim 29. directing light of each of the plurality of corresponding colors in parallel to the phase modulator;
30. The method of claim 29. modifying the collimation of the light for each of the plurality of corresponding colors to form an image at the same point relative to the light modulating element;
33. The method of claim 32. 1. An apparatus for projecting a color image, comprising:
a plurality of color channels, each associated with a corresponding color and having a light source of the corresponding color;
at least one phase modulator;
A light modulation element;
an optical element arranged to direct light from the light sources for each of the plurality of color channels to illuminate the light-modulating element along a path that includes phase modulation by the at least one phase modulator;
a control system connected to control the light source, the at least one phase modulator, and the light modulation elements to project images in a series of fields, each associated with a corresponding color of one of the plurality of color channels, the control system being operative to configure the light modulation elements to spatially modulate light in the fields according to a pattern corresponding to the corresponding color, and to control the light source of the corresponding color to emit light that is phase modulated by the at least one phase modulator and directed onto the light modulation elements;
the control system is further configured to reset a phase pattern by which the at least one phase modulator modulates the light into each of the plurality of color channels at a frequency less than a frequency at which the series of fields is presented;
The apparatus further comprises a polarizing beam splitter upstream of the light modulation element;
the polarizing beam splitter is configured to combine the additional light of the corresponding color with the light steered by the at least one phase modulator;
the light steered by the at least one phase modulator has a first polarization and the additional light has a second polarization different from the first polarization.
Device.